Which implies Ran's not like Chen where the shiki and the bakeneko are distinct beings.
So really this Doujin's at least lore friendly if not accurate
Alas, the words "but in her case" were entirely added by the translator. Without them, the original just says that this is the same situation as Ran. Heck, further up in that same article it says "Ran Yakumo is strictly the shikigami, and the nine-tailed fox youkai she is possessing is an entirely different being." Although, "since the original fox never shows on the surface at all, there's no problem in thinking of Ran Yakumo as a nine-tailed fox." The reason Chen's shiki possession comes off more easily is because her programming is shoddy.
Translation issues aside, I advise against using Who's Who as a source in the first place. The articles are basically wiki-level summaries not written by ZUN, and thus either verifiable from better primary sources or not reliable at all. Mostly they don't really contain any new information, and when they seem to, it's people getting hung up on word choices.
That being said, it is stated in canon that Ran has a tendency to kinda forget her nature as a shikigami (as well as that a master's relationship with the shikigami, the original body aside, doesn't really equal mind control). So the story still makes sense from that perspective.